Absolutely. As one of our great American sages recognized, "It's only work if somebody makes you do it"[0].
The corollary being that a hobby can stop being fun when you stop being able to freely put it down when you want to -- when you've barked your knuckles on the chainring for the 33rd time. And it's also pretty clearly backed up by studies that show that autonomy is a strong factor in workplace happiness and effectiveness.
But I don't buy into that, I believe that you can lose the joy just as much, or more, when you are following the self-employed model.
Working for a boss it's still quite possible (but maybe not easy) to separate work hours from leasure projects in the same fields, but when self-employed, all "off" projects have the potential to become "on" or something in between.
Yeah, there being another person involved isn't the issue, I think, it's that (ultimately) you either do the work or you don't eat. Which is never the case when it's "just a hobby".
So the golden path in keeping a hobby on the fun side is to select one that is sufficiently expensive to never ever be at risk of seeing a break-even line at the horizon.
The corollary being that a hobby can stop being fun when you stop being able to freely put it down when you want to -- when you've barked your knuckles on the chainring for the 33rd time. And it's also pretty clearly backed up by studies that show that autonomy is a strong factor in workplace happiness and effectiveness.
[0]:https://www.gocomics.com/calvinandhobbes/1989/08/28